Tire Pressure

*My* gut says 30 isn't enough, but who knows.

I would start with 30-35, and keep a very critical eye on treadwear. If it wears faster on the outside, increase pressure. If it wears on the center, decrease pressure.

The wife's car is a 2003 Stratus. At 30PSI the tires are wearing evenly (with 35K miles on them). At 44PSI surely they would wear in the center treads and decrease overall tire life. Also, harder tire pressures add wear to suspension components and reduce wet traction.

The wife's car is a 2003 Stratus. At 30PSI the tires are wearing evenly (with 35K miles on them). At 44PSI surely they would wear in the center treads and decrease overall tire life. Also, harder tire pressures add wear to suspension components and reduce wet traction.

Always go by the sticker that is on the door jam and not by the tire manufacture.

Glenn Beasley Chrysler Tech

Why would the auto manufacture know more about tires than the tire manufacture? The auto manufacture cares about ride quality and handling. Not tire wear. Recall that Ford stipulated different tire pressure than Firestone to improve handling but possibly leading to some of the blowouts.

The tire has no idea what the vehicle weights or anything else about the vehicle. Always go by the rating on the vehicle. Firestone made a poor quality tire.

Glenn

A couple of additional thoughts.

1. The "maximum pressure" is just that. A safety warning from the tire manufacturer. If you inflate it beyond that point the expansion of the air under driving conditions might be enough to damage the tires or even a blowout. Myself has never wanted to test just how much safety margin the makers put in this recommendation. As such I feel pretty confident that it has no relation to either comfort of ride, fuel economy, nor tire wear.
2. I heard (during/after the Ford Explorer tire debacle) a recommendation from someone knowledgeable to inflate to 4 pounds under the max pressure rating for optimal safety of infation (not necessarily the best ride nor best fuel economy).
3. While I'm sure the car mfg. does know the gross weight of the vehicle (and so do you since they include it on the label plate) and have tested how it handles at various tire pressures, they don't know whether the car is driven with little to no extra weight or fully loaded like you were moving everyday (the traveling salesman selling floor tile with mega samples type). The more weight you ad to the car, the more inflation you need to add to the mfg. recommendation. (I think they would agree?)
4. Alignment is, in my humble experience, a more important factor for good tire wear than even inflation. Yes, very over or under inflation is both dangerous and will cause rapid wear. But so will excessive toe in/ toe out etc. Best time to align is with new tires. Bob

In a few more years when all cars being made will be required to have tires sensors built in for emissions, you wont have to worry about that because if the tire pressure is below or exceeds the programmed value it will turn on the warning lite. So if you have a tire that is rated at 50psi and you top it off to 50psi and the vehicle is rated at 35psi.....you will be staring at the yellow lite on the dash until you set them to specs.

Glenn Beasley Chrysler Tech

I see comments like this all this time and cannot understand why anyone would read the maximum tire pressure on the sidewall and take that as a reocmmended pressure. It is a "Do Not Exceed This Pressure" warning, not a recommendation.

I guess tire companies should put "Follow vehicle manufacturer >

I always go buy what the automaker recommends, but keep an eye on the tires for some small adjustments.

maxpower wrote:

That really isn't true. The rating on the sidewall gives the maximum loading capability of the tire. It gives the PSI required to achieve that load rating.

The Complete Tire Safety Guide We at Goodyear are keenly aware of how important tires are to the safety of any driver. That is why we have assembled this guide to assist in the proper care and maintenance of your tires, so that you can enjoy maximum performance and driving security. Click on the Tire Safety Guide image on the right.

WARNING: Before you replace your tires, always consult the vehicle owner's manual and follow the vehicle manufacturer's replacement tire recommendations. Vehicle handling may be significantly affected by a change in tire size or type. When selecting tires that are different from the original equipment size, see a professional installer in order to make certain that proper clearance, load carrying capacity and inflation pressure is selected. Never exceed the maximum load capacity and inflation pressure listed on the sidewall of the tire. Always drive safely and obey all traffic laws. Avoid sudden, sharp turns or lane changes. Failure to follow this warning may result in loss of control of the vehicle, leading to an accident and serious injury or death.

My statement still holds true. Exceeding the PSI listed on the sidewall will reduce the loading capabilities of the tire. So will reducing the PSI. However, handling issues may supersede load requirements and thus an auto manufacture may opt for a reduced PSI. T

When I put ContiExtremeContact tires on my Saturn SL2 I tried the tire pressure as listed in the door frame. The car was very loose and squirrelly, dangerously so. I gradually increased the tire pressure until it felt safe and comfortable. The stock tires had a max pressure of 35psi, while the Conti's had a max of 44psi.

Ken

You seemed to imply that the PSI shown on the sidewall is not the correct PSI for a tire. It certainly is if you want the tire to be capable of handling its designed loading capabilities. A vehicle manufactures door sticker often lists a lower value to improve ride nquality. Depending on vehicle/tire combination this may or may not be such a good idea. Ride quality based on tire PSI is a compromise for safety, handling and loading abilities.